diff options
| -rw-r--r-- | Documentation/i2c/dev-interface | 32 | ||||
| -rw-r--r-- | drivers/i2c/busses/Kconfig | 3 | ||||
| -rw-r--r-- | drivers/i2c/busses/i2c-sprd.c | 22 | ||||
| -rw-r--r-- | drivers/i2c/i2c-dev.c | 2 |
4 files changed, 33 insertions, 26 deletions
diff --git a/Documentation/i2c/dev-interface b/Documentation/i2c/dev-interface index d04e6e4964ee..fbed645ccd75 100644 --- a/Documentation/i2c/dev-interface +++ b/Documentation/i2c/dev-interface @@ -9,8 +9,8 @@ i2c adapters present on your system at a given time. i2cdetect is part of the i2c-tools package. I2C device files are character device files with major device number 89 -and a minor device number corresponding to the number assigned as -explained above. They should be called "i2c-%d" (i2c-0, i2c-1, ..., +and a minor device number corresponding to the number assigned as +explained above. They should be called "i2c-%d" (i2c-0, i2c-1, ..., i2c-10, ...). All 256 minor device numbers are reserved for i2c. @@ -23,11 +23,6 @@ First, you need to include these two headers: #include <linux/i2c-dev.h> #include <i2c/smbus.h> -(Please note that there are two files named "i2c-dev.h" out there. One is -distributed with the Linux kernel and the other one is included in the -source tree of i2c-tools. They used to be different in content but since 2012 -they're identical. You should use "linux/i2c-dev.h"). - Now, you have to decide which adapter you want to access. You should inspect /sys/class/i2c-dev/ or run "i2cdetect -l" to decide this. Adapter numbers are assigned somewhat dynamically, so you can not @@ -38,7 +33,7 @@ Next thing, open the device file, as follows: int file; int adapter_nr = 2; /* probably dynamically determined */ char filename[20]; - + snprintf(filename, 19, "/dev/i2c-%d", adapter_nr); file = open(filename, O_RDWR); if (file < 0) { @@ -72,8 +67,10 @@ the device supports them. Both are illustrated below. /* res contains the read word */ } - /* Using I2C Write, equivalent of - i2c_smbus_write_word_data(file, reg, 0x6543) */ + /* + * Using I2C Write, equivalent of + * i2c_smbus_write_word_data(file, reg, 0x6543) + */ buf[0] = reg; buf[1] = 0x43; buf[2] = 0x65; @@ -140,14 +137,14 @@ ioctl(file, I2C_RDWR, struct i2c_rdwr_ioctl_data *msgset) set in each message, overriding the values set with the above ioctl's. ioctl(file, I2C_SMBUS, struct i2c_smbus_ioctl_data *args) - Not meant to be called directly; instead, use the access functions - below. + If possible, use the provided i2c_smbus_* methods described below instead + of issuing direct ioctls. You can do plain i2c transactions by using read(2) and write(2) calls. You do not need to pass the address byte; instead, set it through ioctl I2C_SLAVE before you try to access the device. -You can do SMBus level transactions (see documentation file smbus-protocol +You can do SMBus level transactions (see documentation file smbus-protocol for details) through the following functions: __s32 i2c_smbus_write_quick(int file, __u8 value); __s32 i2c_smbus_read_byte(int file); @@ -158,7 +155,7 @@ for details) through the following functions: __s32 i2c_smbus_write_word_data(int file, __u8 command, __u16 value); __s32 i2c_smbus_process_call(int file, __u8 command, __u16 value); __s32 i2c_smbus_read_block_data(int file, __u8 command, __u8 *values); - __s32 i2c_smbus_write_block_data(int file, __u8 command, __u8 length, + __s32 i2c_smbus_write_block_data(int file, __u8 command, __u8 length, __u8 *values); All these transactions return -1 on failure; you can read errno to see what happened. The 'write' transactions return 0 on success; the @@ -166,10 +163,9 @@ what happened. The 'write' transactions return 0 on success; the returns the number of values read. The block buffers need not be longer than 32 bytes. -The above functions are all inline functions, that resolve to calls to -the i2c_smbus_access function, that on its turn calls a specific ioctl -with the data in a specific format. Read the source code if you -want to know what happens behind the screens. +The above functions are made available by linking against the libi2c library, +which is provided by the i2c-tools project. See: +https://git.kernel.org/pub/scm/utils/i2c-tools/i2c-tools.git/. Implementation details diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index c4865b08d7fb..8d21b9825d71 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -707,7 +707,6 @@ config I2C_MPC config I2C_MT65XX tristate "MediaTek I2C adapter" depends on ARCH_MEDIATEK || COMPILE_TEST - depends on HAS_DMA help This selects the MediaTek(R) Integrated Inter Circuit bus driver for MT65xx and MT81xx. @@ -885,7 +884,6 @@ config I2C_SH7760 config I2C_SH_MOBILE tristate "SuperH Mobile I2C Controller" - depends on HAS_DMA depends on ARCH_SHMOBILE || ARCH_RENESAS || COMPILE_TEST help If you say yes to this option, support will be included for the @@ -1098,7 +1096,6 @@ config I2C_XLP9XX config I2C_RCAR tristate "Renesas R-Car I2C Controller" - depends on HAS_DMA depends on ARCH_RENESAS || COMPILE_TEST select I2C_SLAVE help diff --git a/drivers/i2c/busses/i2c-sprd.c b/drivers/i2c/busses/i2c-sprd.c index 25fcc3c1e32b..4053259bccb8 100644 --- a/drivers/i2c/busses/i2c-sprd.c +++ b/drivers/i2c/busses/i2c-sprd.c @@ -86,6 +86,7 @@ struct sprd_i2c { u32 count; int irq; int err; + bool is_suspended; }; static void sprd_i2c_set_count(struct sprd_i2c *i2c_dev, u32 count) @@ -283,6 +284,9 @@ static int sprd_i2c_master_xfer(struct i2c_adapter *i2c_adap, struct sprd_i2c *i2c_dev = i2c_adap->algo_data; int im, ret; + if (i2c_dev->is_suspended) + return -EBUSY; + ret = pm_runtime_get_sync(i2c_dev->dev); if (ret < 0) return ret; @@ -364,13 +368,12 @@ static irqreturn_t sprd_i2c_isr_thread(int irq, void *dev_id) struct sprd_i2c *i2c_dev = dev_id; struct i2c_msg *msg = i2c_dev->msg; bool ack = !(readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK); - u32 i2c_count = readl(i2c_dev->base + I2C_COUNT); u32 i2c_tran; if (msg->flags & I2C_M_RD) i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD; else - i2c_tran = i2c_count; + i2c_tran = i2c_dev->count; /* * If we got one ACK from slave when writing data, and we did not @@ -408,14 +411,13 @@ static irqreturn_t sprd_i2c_isr(int irq, void *dev_id) { struct sprd_i2c *i2c_dev = dev_id; struct i2c_msg *msg = i2c_dev->msg; - u32 i2c_count = readl(i2c_dev->base + I2C_COUNT); bool ack = !(readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK); u32 i2c_tran; if (msg->flags & I2C_M_RD) i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD; else - i2c_tran = i2c_count; + i2c_tran = i2c_dev->count; /* * If we did not get one ACK from slave when writing data, then we @@ -586,11 +588,23 @@ static int sprd_i2c_remove(struct platform_device *pdev) static int __maybe_unused sprd_i2c_suspend_noirq(struct device *pdev) { + struct sprd_i2c *i2c_dev = dev_get_drvdata(pdev); + + i2c_lock_adapter(&i2c_dev->adap); + i2c_dev->is_suspended = true; + i2c_unlock_adapter(&i2c_dev->adap); + return pm_runtime_force_suspend(pdev); } static int __maybe_unused sprd_i2c_resume_noirq(struct device *pdev) { + struct sprd_i2c *i2c_dev = dev_get_drvdata(pdev); + + i2c_lock_adapter(&i2c_dev->adap); + i2c_dev->is_suspended = false; + i2c_unlock_adapter(&i2c_dev->adap); + return pm_runtime_force_resume(pdev); } diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c index 036a03f0d0a6..1667b6e7674f 100644 --- a/drivers/i2c/i2c-dev.c +++ b/drivers/i2c/i2c-dev.c @@ -280,7 +280,7 @@ static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client, */ if (msgs[i].flags & I2C_M_RECV_LEN) { if (!(msgs[i].flags & I2C_M_RD) || - msgs[i].buf[0] < 1 || + msgs[i].len < 1 || msgs[i].buf[0] < 1 || msgs[i].len < msgs[i].buf[0] + I2C_SMBUS_BLOCK_MAX) { res = -EINVAL; |